Hi brenticus,
is it possible to run backburner with the vray frame buffer on? If it is, just turn on the option "save seperate render channels" in the vray render dialog under "vray: frame buffer". Then the elements should be saved in the same folder as your rendering does (the one you set up in the vray: frame buffer dialog). in this option every render element gets a own exr- sequence.
I din“t try this with the backburner but without it definitely works.
cheers